Enantioselective nucleophilic difluoromethylation of aromatic aldehydes with Me3SiCF2SO2Ph and PhSO2CF2H reagents catalyzed by chiral quaternary ammonium salts.
BACKGROUND
Although the nucleophilic difluoromethylation of aldehydes, ketones, and imines has been realized with PhSO(2)CF(2)H and related reagents, there are still no reports on the enantioselective nucleophilic reactions.


RESULTS
With a chiral quaternary ammonium salt as the catalyst and KOH as the base, we describe the first enantioselective difluoromethylation of aromatic aldehydes with PhSO(2)CF(2)H or Me(3)SiCF(2)SO(2)Ph. The enantioselectivity is substrate-dependent and for 2-chlorinated benzaldehyde an ee up to 64% was obtained.


CONCLUSIONS
These results provide some insights into the enantioselective nucleophilic difluoromethylation chemistry, which will stimulate further progress in this field.
Ni
Chuanfa
C
Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, China.
Wang
Fang
F
Hu
Jinbo
J